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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

39194 results found.

  1. Fermi GRB 240910A: Global MASTER-Net observations report
  2. GRB 240910A: Fermi GBM Final Real-time Localization
  3. LIGO/Virgo/KAGRA S240908bs: Upper limits from Swift/BAT-GUANO
  4. LIGO/Virgo/KAGRA S240907cg: Upper limits from Swift/BAT-GUANO
  5. EP EP240908a: Global MASTER-Net observations report
  6. GRB 240905B: Fermi GBM Observation
  7. Fermi trigger No 747553301: Global MASTER-Net observations report
  8. EP240908a: TRT optical upper limit
  9. GRB 240905B: GOTO optical upper limits
  10. Fermi GRB 240908A: Global MASTER-Net observations report
  11. GRB 240908A: Fermi GBM Final Real-time Localization
  12. GRB 240801A: SVOM/GRM observation
  13. GRB 240905E: GIT optical upper limit
  14. GRB 240905B: Swift-XRT observations
  15. GRB 240905E: Gaoyazi/GOT optical upper limits
  16. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  17. GRB 240905B: Fermi-LAT detection
  18. GRB 240905B: Swift ToO observations
  19. GRB 240905E: J-band observations with WINTER
  20. GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
  21. GRB 240905E: AKO Optical Upper Limit
  22. GRB 240905E: SVOM/C-GFT optical upper limit
  23. GRB 240905E: OHP/MISTRAL T193 optical upper limit
  24. Fermi GRB 240905D: Global MASTER-Net observations report
  25. Fermi GRB 240905A: Global MASTER-Net observations report
  26. GRB 240905E: NOT optical upper limits
  27. GRB 240905E: REM optical/NIR upper limits
  28. GRB 240902B: AstroSat CZTI detection of a long burst
  29. GRB 240905E: Swift-XRT refined Analysis
  30. GRB 240902A: AstroSat CZTI detection of a long burst
  31. GRB 240905E: SVOM/GRM observation
  32. GRB 240905E: LCOGT Optical Upper Limit
  33. GRB 240905E: Swift/UVOT Upper Limits
  34. GRB 240905E: SAO RAS optical upper limit
  35. GRB 240825A: Montarrenti Observatory optical follow-up observations
  36. GRB 240905E: Nanshan/HMT optical upper limit
  37. Swift GRB 240905E: Global MASTER-Net observations report
  38. GRB 240905E: Swift detection of a burst
  39. GRB 240819A: Optical upper limits from TESS
  40. GRB 240905D: AstroSat CZTI detection
  41. GRB 240905A: SVOM/GRM observation
  42. Fermi GRB 240905B: Global MASTER-Net observations report
  43. GRB 240905D: Fermi GBM Final Real-time Localization
  44. GRB 240905B: AstroSat CZTI detection and localization
  45. GRB 240905C: Fermi GBM Final Real-time Localization
  46. GRB 240905B: Fermi GBM Final Real-time Localization
  47. GRB 240825A: ATCA Detection of Radio Counterpart
  48. Swift GRB 240904A: Global MASTER-Net observations report
  49. GRB 240905A: Fermi GBM Final Real-time Localization
  50. Fermi Gamma-ray Burst Monitor trigger 747163821/240904729 is not a GRB
  51. Fermi trigger No 747163821: Global MASTER-Net observations report
  52. GRB 240904A: Swift detection of a burst
  53. GRB 240828A: SVOM/GRM observation
  54. LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
  55. LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
  56. Fermi Gamma-ray Burst Monitor trigger 240831A is not a GRB
  57. GRB 240828A: GECAM detection
  58. GRB 240831B: Fermi GBM Final Localization
  59. Fermi Gamma-ray Burst Monitor trigger 746882332/240901471 is not a GRB
  60. GRB 240825A: Magnitude Correction in SVOM/C-GFT Optical Observations
  61. GRB 240825A: MeerLICHT afterglow detection
  62. Fermi trigger No 746923430: Global MASTER-Net observations report
  63. GRB 240828A: SAO RAS AS-500(2) optical observations
  64. GRB 240821A: VLT spectroscopic observations
  65. Fermi trigger No 746882332: Global MASTER-Net observations report
  66. GRB 240825A: TSHAO Optical Upper Limit
  67. GRB 240829B: GRBAlpha detection
  68. GRB240828B: REM optical/NIR upper limits
  69. Fermi trigger No 746816563: Global MASTER-Net observations report
  70. GRB 240828B: AbAO optical upper limit
  71. GRB 240831A: Fermi GBM Final Real-time Localization
  72. GRB 240825A: SOAR observations
  73. GRB 240828B: Mephisto optical upper limit
  74. GRB 240828B: GRANDMA Optical Upper Limit
  75. GRB 240829A: Swift-BAT refined analysis
  76. GRB 240825A: Swift-BAT refined analysis
  77. GRB 240825A: MeerKAT detection
  78. GRB 240828B: J-band upper limit from WINTER
  79. Fermi trigger No 746684112: Global MASTER-Net observations report
  80. GRB 240828B: GMG Optical Upper Limit
  81. GRB 240828A: KAIT continued optical observations
  82. GRB 240828B: GWAC-F50A optical upper limit
  83. GRB 240828B: SVOM/C-GFT optical upper limit
  84. GRB 240828B: SAO RAS optical upper limit
  85. GRB 240828B: KAIT optical upper limit
  86. GRB 240828A: SAO RAS optical observations
  87. Fermi trigger No 746587425: Global MASTER-Net observations report
  88. GRB 240829B: Fermi GBM Final Localization
  89. GRB 240828A: Fermi GBM Observation
  90. GRB 240629A: First GRB Detected by BurstCube
  91. GRB 240828A: KAIT Optical Afterglow Candidate
  92. GRB 240825A: SVOM/VT optical detection
  93. GRB 240828A: Swift-XRT afterglow detection
  94. GRB 240825A: further SAO RAS optical observations
  95. GRB 240825A: iTelescope optical observations
  96. GRB 240828B: Swift-XRT afterglow detection
  97. GRB 240829A: Swift detection of a burst
  98. Swift GRB240829.16: Global MASTER-Net observations report
  99. GRB 240828A: Fermi-LAT detection
  100. GRB 240828A: Tiled Swift observations

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